In my post #71, I mention some medical research about kidney problems. There was a mention of hemodialysis (one of several dialysis techniques). Are you familiar with that, or how often it's used? It caught my attention because one of the side-effects of hemodialysis is bloating, which might explain why UBL looked so bloated in the confession tape.
There's also mention that a symptom of untreated renal failure would be a yellow/brown or even pasty white complexion, which UBL certainly displayed in the last video.
Is it possible that UBL had a hemodialysis treatment in Kandahar (which is where it is presumed he made the confession tape), and after escaping to the mountains had no dialysis and thus began succumbing to renal failure with its telltale symptoms?
Peritoneal dialysis can certainly create bloating; it blew me up by 35 pounds as my access graft was created and matured. Hemodialysis itself should reduce fluid; most hemodialysis patients end up looking rather thin and wasted, with rather poor complexions. In between treatments, you can definitely puff up as your body builds up fluids.
If bin Laden is a dialysis patient, he would require three treatments a week (usually). He's a technician; he can figure out how to get this done, but it would be very, very difficult to do consistently for a man on the run and hiding. The treatments also freeze you in place for four hours at a time. This is also (obviously) difficult when bombs are falling.
The other type of dialysis is CAPD--using the peritoneal membrane as an 'artificial' kidney to separate out the waste products.